The goal of the Chemoprevention of Skin Cancer (CSC) Biometry Core is to provide data management and computing support for all projects, and to collaborate with project investigators in the development and application of statistical methods for design and analysis. This goal is achieved through the following specific aims: 1. To provide statistical collaboration in the design and execution of all projects, including development of procedures for data collection and maintenance of computer databases for information storage and retrieval. 2. To provide interim reports on individual study progress. 3. To provide statistical analysis of data and participate in writing manuscripts for publication. 4. To provide karyometric analysis of data and develop innovations in karyometry. Biometry support is required in all phases of program studies. During study design the core staff addresses statistical power and sample size issues, and works with study investigators to establish data management and quality control procedures. They also participate in the management, oversight and interim reporting of ongoing studies. Upon study completion, core personnel perform statistical analyses appropriate to the nature of the data in each study in collaboration with study investigators. They also prepare and assist in the preparation of manuscripts for publication. The Biometry Core continues to be used by all program investigators in both clinical and laboratory settings.